A self-revealing
NCV of Improved Technical Specification (
ITS) 5.6.1.1.a was identified for the failure to follow the provisions of preventative maintenance procedure
PM-126, Electrical Checks of
CRD [Control Rod Drive] Power Train. Failure to follow
PM-126 caused the failure of the Group 7
control rod programmer during maintenance and resulted in the unexpected insertion of the Group 7
control rods fully into the core. This unexpected insertion of these
control rods into the core caused control room operations personnel to manually trip the reactor from 100 percent power. The licensee entered this issue into the corrective action program as
NCR 351705. This finding was determined to be more than minor because it was associated with the
initiating events cornerstone attribute of Human Performance, and adversely affected the cornerstone objective to limit the likelihood of those events that upset plant stability and challenge critical safety functions during at-power operations. The finding was evaluated using Phase 1 of the At-Power
SDP, and was determined to be of very low safety significance (Green) because it did not contribute to both the likelihood of a
reactor trip and the likelihood that mitigating equipment or functions were not available. The cause of this finding was directly related to the cross-cutting area of Human Performance with a work practices aspect (H.4 (b)). Specifically, the workers failed to follow the preventative maintenance procedure
